TOTP with SSH (Google Auth)

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For your ssh you can use google-authenticator-libpam to add time based codes to your ssh login.

On debian/ubuntu:

    sudo apt update && sudo apt install google-authenticator-libpam

    google-authenticator

    Do you want authentication tokens to be time-based (y/n) y
    [...]
    Do you want me to update your "/home/dugite/.google_authenticator" file? (y/n) y
    [...]

You will see a QR code/secret key that you can scan with a TOTP app like andotp, authy or google authenticator (WARNING Google authenticator has no backup options). There are also your emergency scratch codes.

In /etc/ssh/sshd_config Add:

    # Use Challenge Response Auth i.e. TOTP
    ChallengeResponseAuthentication yes
    # Require both publickey and TOTP
    AuthenticationMethods publickey,keyboard-interactive

In /etc/pam.d/sshd

    # Comment out Standard Un*x authentication.
    # @include common-auth
    # Load the google TOTP Authentication module
    auth required pam_google_authenticator.so

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